stmmac: fix PWRDWN into the PMT register for global unicast.

MAC devices use the RWKPKTEN and MGKPKTEN bits of the PMT Control/Status
register to generate power management events.
So this patch is to properly set the RWKPKTEN [BIT(2)] inside the
PMT register (needed in case of global unicast).

Reported-by: Aditi SHARMA <aditi-hed.sharma@st.com>
Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Cc: Alexandre TORGUE <alexandre.torgue@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c

@@ -261,7 +261,7 @@ static void dwmac1000_pmt(struct mac_device_info *hw, unsigned long mode)
 	}
 	if (mode & WAKE_UCAST) {
 		pr_debug("GMAC: WOL on global unicast\n");
-		pmt |= global_unicast;
+		pmt |= power_down | global_unicast | wake_up_frame_en;
 	}
 
 	writel(pmt, ioaddr + GMAC_PMT);

drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c

@@ -102,7 +102,7 @@ static void dwmac4_pmt(struct mac_device_info *hw, unsigned long mode)
 	}
 	if (mode & WAKE_UCAST) {
 		pr_debug("GMAC: WOL on global unicast\n");
-		pmt |= global_unicast;
+		pmt |= power_down | global_unicast | wake_up_frame_en;
 	}
 
 	writel(pmt, ioaddr + GMAC_PMT);